Presence information is increasingly being collected in telecommunications networks in order to provide value-added services to telecommunications subscribers. Presence information refers to information regarding the reachability, location, communication terminal status, preferred contact mode, available contact modes, and/or other aspects associated with contacting a telecommunications subscriber. Such information may be collected so that an application or another subscriber can contact and communicate with the subscriber.
The subscriber about whom presence information is being collected is referred to as a presentity. Presence information regarding the presentity is stored by a presence server. When another subscriber or application seeks to contact the presentity, the subscriber or application subscribes to the presentity by sending a subscription message to the presence server. Once the presence server accepts the subscription, the presence server will communicate presence information regarding the presentity to the subscriber or application. When the status of the presentity changes, the presence server will automatically communicate changes in status to the subscribing application or subscriber.
In 3 G communications networks, end user devices, such as GPRS handsets, include presence clients that automatically maintain presence information for subscribers and communicate the presence information to a presence server. In 2 G and 2.5 G networks, end user devices are typically not capable of maintaining or communicating presence information to a presence server. However, since 2 G and 2.5 G network subscribers represent a large percentage of subscribers, it is desirable to collect or derive presence information regarding these subscribers. Commonly-assigned, co-pending U.S. patent application Ser. No. 11/077,711 filed Mar. 11, 2005, the disclosure of which is incorporated herein by reference in its entirety, discloses a presence gateway that automatically derives presence information regarding subscribed-to and non-subscribed-to presentities and delivers the information to a presence server. The presence gateway includes a correlator that correlates signaling messages and derives presence information and an event manager that receives the presence information from the correlator and sends the presence information to the presence server. The event manager receives subscriptions from the presence server and communicates changes in presence information for subscribed-to presentities to the presence server.
As applications that require presence information become increasingly popular, it is desirable to scale the presence gateway architecture to correlate presence information for increasingly large numbers of subscribers. In order to accommodate increasingly large numbers subscribers, multiple presence gateways with multiple correlators and multiple event managers may be used. One problem associated with using multiple correlators and multiple event managers is that the correlators and the presence servers must know the location of the event managers containing presence information for particular subscribers. One potential solution to the problem is to statically configure each correlator and presence server with a location of the event manager with presence information for each subscriber. Statically configuring the correlators and presence servers with the location of the presence information for each subscriber is cumbersome and requires manual re-provisioning as new subscribers are added to the network.
Accordingly, in light of the problems associated with collecting and distributing presence information, there exists a need for improved methods, systems, and computer program products for coordinating collection and distribution of presence information.